Plug valves having relieved high pressure seal areas



March 3, 1970 ,-w, FF 3,498,318

PLUG VALVES HAVING RELIEVED HIGH PRESSURE SEAL AREAS Filed March 22,1968 2 Sheets-Sheet 1 FIG -1 I0 5| 50 l 2 36 1 as 49 8| 63 43 h 25 6| 2l5 2 T a 11 INVENZ'OR DONN W. DUFFEY W WM? 3 March 3, 1970 o. w. DUFFEYPLUG VALVES HAVING RELIEVED HIGH PRESSURE SEAL AREAS Filed March 22,1968 FIG-4 2 Sheets-Sheet 2 United States Patent 3,498,318 PLUG VALVESHAVING RELIEVED HIGH PRESSURE SEAL AREAS Donn W. Duffey, Dayton, Ohio,assignor to The Duriron Company, Inc., Dayton, Ohio, a corporation ofNew York Filed Mar. 22, 1968, Ser. No. 715,434 Int. Cl. F16k 5/02,27/06, 25/00 U.S. Cl. 137-375 Claims ABSTRACT OF THE DISCLOSURECorrosion resistant plug valves including a polytetrafluoroethylene(PTFE) sleeve seal element wherein the sleeve is secured against axial,radial and deflecting movements are described. The valve body has apattern of relief areas in the bore such that the portions of the sleevein the relief areas are under relatively high sealing pressure. Therelief areas include top and bottom axially spaced circumferentiallyextending relief bands joined together by axially extending relievedsections arcuately spaced from angularly disposed body ports to providea flange on each side of the body ports. The bore above and below thebody ports is also relieved so that the flanges form axially extendingbore flanges at the junction of the ports and the bore to preventrotation of the sleeve. Spaced arcuately from the flanges and betweenthe ports are bore areas which are not relieved and which also act toprevent rotation of the sleeve. The surface of the sleeve includesrelieved areas opposite the portion of the bore between the ports.Two-way and multiple port valves as well as fully lined sleeve valvesare also described.

BACKGROUND OF THE INVENTION The present invention relates to corrosionresistant plug valves and more particularly to improved dual andmultiple port plug valves in which the sleeve is secured againstmovement and displacement by an improved body construction.

Sleeve lined plug valves are known in which the seal element is atubular member of PTFE secured against the body to prevent rotationalmovement thereof, see U.S. Patents 2,961,214 and 3,206,163. U.S. Patent2,728,550 describes a non-circular sleeve received within a non-circularbore to prevent rotation of the sleeve. U.S. Patent 2,987,295 describesa valve structure in which blow-out of the sleeve is prevented whenturning the valve from the open to the closed position, and US. Patent3,199,835 describes a structure in which a harness type seal element isused in a body which includes annular shoulders at the inner ends of theport to prevent movement of the sleeve with respect to the body. Thislatter patent also describes annular shoulders projecting into the boreto prevent movement of a tubular sleeve element. All of the abovepatents are assigned to the present assignee.

Also of interest in sleeve lined plug valves is U.S. Patent 3,061,269 inwhich high pressure seal areas are obtained by compressing portions ofthe sleeve beyond the elastic limits of PTFE, and U.S. Patent 3,066,909in which holes are provided in the sleeve to prevent rupture or turningthereof in turning the plug from the open to the closed position.

U.S. Patent No. 3,263,697 describes a valve structure utilizing ashiftable plug for use as a socalled fire safe valve. This latter valvealso includes continuous shoulders projecting into the bore of the bodyand shows relief areas in the body spaced between the ports. The thickerportions of the sleeve received in the relief areas are under PatentedMar. 3, 1970 low sealing pressure as compared to the thinner portions ofthe sleeve.

Reference is made to application Ser. No. 715,433, filed Mar. 22, 1968,and assigned to the same assignee.

SUMMARY OF THE INVENTION The present invention differs from the abovenoted patents by the provision of a plug valve in which the bodyincludes a frusto-conical bore which receives a full frustoconicalsleeve. The bore includes a pattern of relief areas therein whichreceive the sleeve, the portions of the sleeve received in the reliefareas being under high sealing pressure as compared to the portions ofthe sleeve which are not received in the reliefs in the body. Thepattern of relief areas includes axially spaced reliefs above and belowthe angularly spaced ports in the body and relieved sectionscommunicating with the top and bottom of each port. Also provided arearcuately spaced axially extending reliefs spaced on each side of thebody ports to form flanges between the body ports and the axiallyextending reliefs, the flanges defining the radial dimension of thebore. The sleeve is sufficiently thick in cross-sectional dimension tomaintain the plug spaced from the flanges which extend axially along theport and which form the junction of the port and the bore. The bore alsoincludes portions between the angularly spaced ports which separate theaxially extending relief sections, while the portion of the sleevefacing these bore portions are relieved to provide relatively lowpressure seal areas. The bore of the body includes a base, which in thecase of a multiple port valve includes a port, the plug beingregistrable with one or the other of the angularly disposed ports andthe port in the base.

The body further includes grooves above and below the angularly spacedports to prevent axial movement of the sleeve. In the case of largervalves, that is, three inches and up, it is desirable to use pressurerelief means in the Sleeve to vent the back side of the sleeve when theplug is being rotated from the open to the closed position, especiallywhere the valve is operating under conditions of relatively hightemperature and/or pressure. It is also desirable to utilize pressurecommunication diaphragms in the sleeve which rupture at a predeterminedpressure to prevent rotation or damage to the sleeve when rotatingtheplug from the closed to the open position. If desired, all interiorsurfaces of the body may be coated with a corrosion resistant coating,and the plug may also have all surfaces thereof coated with a corrosionresistant coating.

Accordingly, a primary object of the present invention is the provisionof an improved corrosion resistant plug valve in which a frusto-conicalbody bore is constructed to provide high pressure seal areas in thethicker portion of a frusto-conical sleeve which is received between theclosure member and the bore, while the thinner portions of the sleeveare at a lower sealing pressure.

Another object of the present invention is the provision of an improvedplug valve of the type described in which the frusto-conical body boreis recessed and receives a sleeve which is preformed and pre-ported andhaving a configuration which essentially matches that of the body borethereby substantially reducing the amount of polytetrafluoroethyleneused in the sleeve while providing a valve which seals efliciently overa wide range of temperatures and pressure.

Still another object of the present invention is the provision of animproved plug valve of the type described in which the sleeve issecurely anchored to prevent axial and rotational movement thereof, thethicker portions of the sleeve being under relatively high sealingpressure, and in the case of larger valves exposed to relatively hightemperatures and pressures, the sleeve is provided with pressurepassages which prevent deflection of the sleeve into the plug port asthe plug is rotated from the open to the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in axial section andpartly in elevation of a plug valve in accordance with the presentinvention;

FIG. 2 is a sectional view taken along the lines 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along the lines 3-3 of FIG. 2 with aportion of the sleeve broken away to show the interior of the valvebody;

FIG. 4 is a view in perspective of a sleeve used in the valve of thepresent invention;

FIG. 5 is a sectional view taken along the lines 5-5 of FIG. 4;

FIG. 6 is a view similar to FIG. 1 showing a multiple port valve inaccordance with the present invention; and

FIG. 7 is a fragmentary sectional view showing a fully lined sleevevalve in accordance with the present invention.

Referring to the drawings, which illustrate a preferred embodiment ofthe present invention, FIGS. 1-3 show a corrosion resistant valve 10which includes a body 12, preferably of a corrosion resistant materialsuch as a metal or metal alloy. The body 12 includes a frustoconicaltapered bore 15 extending transversely thereof, the smaller end of thebore being closed by an integrally formed base 16, although this may bea separate member, if desired.

Communicating with the bore 15 are angularly spaced ports 17 and 18which, in the case of a two-way valve are inlet and outlet ports.Received within the bore 15 is a rotatable closure member 20 in the formof a tapered plug and which includes a port 21 communicating with theangularly spaced body ports 17 and 18. The plug 20 is of a smallerradial dimension than the radial dimensions of the bore to form anannular clearance between the outer surface of the plug and the bore.

Received within the annular clearance is a tubular sleeve 25, the sleevebeing frusto-conical in shape and being of polytetrafluoroethylene, afluorocarbon resin which has a coefficient of thermal expansion greaterthan that of the plug or body and which is relatively chemically inert.The sleeve, which is of a cross-sectional dimension suflicient tomaintain the plug spaced from the bore, includes ports therein, asshown, which communicate with the angularly spaced body ports.Positioned over the open end of the bore is a top cap assembly generallydesignated and including a cap member secured to the valve body by bolts36, the inner portion of the cap being sealed on a shoulder which isformed in a counterbore 41 at the open end of the bore. Positionedbetween the shoulder 40 and the cap 35 is an annular thrust diaphragm 43of PTFE.

The plug 20 includes a stem 44 which projects through the cap 35, thestem being provided with flats 46 on each side thereof for lockingengagement with an operating member in the usual way. The diaphragm 43is provided with an opening through which the stem 44 extends, with theinner peripheral portion 47 of the diaphragm being in engagement withthe stem. Sealing pressure of the plug with the sleeve 25 is maintainedby means of a gland 48 which surrounds the stem 44 and which engages theupper surface of the plug through an annular disk 49 positioned betweenthe bottom of the gland 48 and the upper surface of the diaphragm 43,the gland 48 being forced against the plug by a gland follower 50adjustably secured to the cap 3 5 by bolts 51.

The body 12 includes flanges 52 provided with bolt holes (FIG. 3) forattachment of the valve to a conduit in the usual manner. It isunderstood, however, that the valve may be of the screwed end type, ifdesired.

Each of the body ports 17 and 18 which open into the bore in angularlyspaced relation includes essentially straight side walls 53- as shown inFIG. 3, and for purposes of this invention, essentially straight sideWalls is intended to include slightly curved side walls. The bore of thebody includes a pattern of indentations thereon which form relief meansin the bore which have a radial dimension greater than the correspondingradial dimension of the bore.

The relief means includes axially spaced top and bottom relief bands 53and 54, respectively, which extend circumferentially on each side of thebore. Joining the relief bands 53 and 54 together are arcuately spacedrelief sections 56, 57 on one half of the bores and relief sections 58and 59 on the other half of the bore, ,the halves of the bore beingidentified with reference to the center line 0 in FIG. 2. Immediatelyabove and below each port 17 and 18 are relief areas 61, 62, 63 and 64,respectively, which with relief bands 53 and 54 form continuous annularreliefs, although interrupted relief areas may be used, if desired.

The relief sections 56, 57, 58 and 59 are arcuately spaced on each sideof the associated body port to form four flanges 71, 72, 73 and 74,respectively, which extend axially approximately the same distance asthe associated port opening. These flanges form the junction between theport and the bore and define the radial dimension of the bore. Therelief sections 56, 57, 5 8 and 59 on the same side of the body areseparated from each other by portions of the bore 76 and 77,respectively, located between the body ports and bounded top and bottomby relief bands 53 and 54. The radial dimensions of the bore portions 76and 77 are the same as the corresponding radial dimensions of the boreflanges 5659, inclusive. Located axially above and below the reliefbands 53 and 54 are grooves 81 and 82, respectively, which have radialdimensions greater than the radial dimensions of the relief areas andwhich operate to prevent axial movement of the sleeve in response tochanges in temperature, and in the case of groove 82, preventsdisplacement of the portion of the sleeve immediately below the portinto the port in the event of accumulation of pressure between thebottom of the plug and the base of the bore. While shown as continuous,it is understood that these grooves may be interrupted.

The sleeve, in accordance with the present invention, is preformed andpre-ported for reception into the bore 15, and the various portions arenumbered with the suifix a being used to identify the portions of thesleeve received in the opposing portion of the bore. As shown in FIGS. 4and 5, the sleeve is relatively thin in areas 76a and 77a which arereceived opposite the portions of the bore 76 and 77, these areasforming relief areas of low sealing pressure and cooperating with thebore and with flanges 56-59 to prevent rotation of the sleeve relativeto the bore and to reduce the turning torque. While the areas 76a and77a are shown in contact with the opposed portions of the bore, it isunderstood that there may be a small space therebetween, or aninterference fit with some slight sealing pressure, depending upon theextent to which the plug is urged axially into the bore. While the termrelief areas is used to describe portions 76a and 77a of the sleeve,these areas in fact are the normal cross-sectional dimension of thesleeve, and the term is used because it decribes the function performedby these portions of the sleeve. Thus, the cross-sectional dimension ofthe sleeve in areas 76a and 77a is sufiicient to maintain the plugspaced from the portions of the body forming the bore, i.e., 71-74 and76 and 77.

The sleeve includes port openings 17a and 18a which have a greaterarcuate dimension than the openings of the corresponding body ports.Portions 56a, 57a, 58a and 59a of the sleeve are of greatercross-sectional dimension than portions 76a and 77a for reception intothe corresponding relief sections 56-59 of the body. The portions 61a,62a, 63a and 64a of the sleeve, immediately above and below the sleeveports are of the same cross-sectional dimensions as the portions 56a59afor reception into relieved portions 61 and 64 of the bore. Immediatelyabove and below each area 76a and 77a of the sleeve are portions 53a and54a which are received in the relief bands 53 and 54 of the bore, whileportions 810 and 82a are received in the grooves 81 and 82. As shown,the cross-sectional dimensions of portions 81a and 82a are greater thanthe cross-sectional dimensions of the portion of the sleeve received inthe relief areas in the body.

The sleeve is easily fabricated by forming a frustoconical blank andmachining the ports and the areas 76a and 77a, or the sleeve may beformed isostatically in which case the ports are cut after processing.The latter procedures oflers the advantages of being able to form atleast a major portion of the areas 76:: and 77a in the moldingoperation. For details on isostatically molding, reference is made toSer. No. 497,869, filed Oct. 19, 1965, and assigned to the sameassignee.

In assembling the sleeve in the body, one of several methods may beused. For example, the sleeve may be chilled to a low temperature andbecause of the high coefiicient of thermal expansion, it contractssufficiently to fit into the bore. As the sleeve warms up it snaps intoplace, and a sizing operation may be used with a dummy plug to insurereception of the sleeve into the appropriate reliefs. There is not,however, the substantial movement of PTFE which occurs in the hot orcold forming procedures described in the previously identified patents.Thereafter, a working plug is inserted into the sleeve and the top capassembly is assembled to the body. Alternately, the sleeve may be coinedto reduce its diameter and assembled into the body, and as the PTFErecovers, the sleeve snaps into place. Again, a sizing plug may be usedif desired. One of the advantages in the valve in accordance with thepresent invention is the ease of assembling the component parts thereof,particularly the sleeve which is preformed to fit the body, and whichmay be assembled thereto without the use of heat or the application ofpressures necessary to deform the sleeve substantially as is describedin some of the preceding patents.

Once assembled, the sleeve is compressed between the plug and the bodyto provide a seal element and bearing surface in which a pattern of highpressure sealing areas is formed for eflicient sealing. The initialdimensions of the sleeve are so coordinated and correlated with the boredimensions and the dimensions of the relief means that the sleeve fitsand seals particularly in the relieved portions of the bore. The patternof high pressure seal areas is defined by portions 53a and 54a at thetop and bottom of the sleeve 56a, 61a, 62a and 58a around one port, and63a, 59a, 64a and 57a around the other port. Each of the relief areas76a and 77a is in turn surrounded by high pressure seal areas as shownin FIGS. 4 and 5. Thus, the thicker portions of the sleeve are at ahigher sealing pressure than the thinner portions, the sleeve beingsecured by being received within the relief means in the bore and theportions of the bore which are received by the reliefs in the sleeve aswell as the portions of the bore which form the flanges 56-59.

The sleeve also includes a pressure burst diaphragm 85 positioned oneach side of the bore and between the ports (FIGS. 4 and 5), andoperative to burst if the pressure between the bore increases above apredetermined minimum as described in application Ser. No. 524,697,filed Feb. 3, 1966, now US. Patent No. 3,383,088, issued May 14, 1968,and assigned to the same assignee. In this way, pressure above apredetermined minimum is vented into the plug port to prevent tearing orturning of the sleeve when the plug is rotated from the closed to theopen position.

It has also been observed, particularly in the case of larger sizevalves, for example, three inches and up used in services at relativelyhigh temperatures and pressures that there is a tendency of the portion58a of the sleeve adjacent the inlet port 17a to deflect inwardly towardthe plug port as the plug is rotated from the open to the closedposition. Essentially the same thing may occur with portions 56a, 57aand 59a of the sleeve depending upon which port is the inlet port andthe direction in which the plug is rotated in order to move from theopen to the closed position. This condition exists, notwithstanding thepresence of the flanges 56-59, because at relatively high temperaturesand pressures in the larger size valves, the PTFE material issufficiently softened to be deflectable into the plug port. Accordingly,in the case of larger valves embodying the principles 'of the presentinvention, the sleeve includes pressure relief means as shown, in dottedlines, which prevent buildup of pressure between the reliefs in the boreand the back side of the sleeve tending to force the sleeve into theplug port on the upstream side as the plug is rotated from the open tothe closed position. By using pressure relief means adjacent each sideof the body ports, the valve is omnidirectional in the direction ofrotation of the plug and in the direction of fluid flow. It isunderstood, however, that in the case of a valve in which the inlet sideis port 17a and the outlet 18a, that is, a unidirectional valve, withrotation of the plug in a clockwise direction, as indicated, in goingfrom the open to the closed position, the pressure relief holes need beused only in portion 58a of the sleeve. In a bi-directional valve inwhich the inlet may be 17a or 18a with the plug being rotated in thesame direction above, in addition to using pressure relief holes inportions 58a of the sleeve, pressure relief holes are also used inportion 57a of the sleeve. Alternatively, a uni-directional valve mayincorporate a downstream closing principle, that is the downstream sideof the valve closes before the upstream side. This may be accomplishedseveral ways, as shown in the patents previously identified.

Referring to FIG. 6 in which like reference numerals have been used, athree-way valve is shown in which the interior portions of the body andthe sleeve are essentially the configuration of the bore and sleevepreviously described. In the three-way valve shown in FIG. 6, the plugincludes a port which is registrable with one or the other of theangularly disposed ports 17 or 18 and with the third port opening intothe bore and formed through the base 16 of the valve body. It is alsounderstood, that other porting arrangements may be employed in multipleport valves as is well known to those skilled in the art.

Satisfactory results have been obtained in a three inch valve exposed totemperatures of 350 F. using a sleeve of about 0.125 inch cross-sectionin portions 76a and 77a of the sleeve, although differentcross-sectional dimensions may be used for larger and smaller valves, orvalves exposed to lower temperatures, as will be apparent to thoseskilled in the art.

FIG. 7 illustrates a modified form of the present invention in which allportions of the interior of the bore and the ports are coated with acorrosion resistant plastic coating shown as the stippled portions, thecoating in the portion of the bore being interposed between the sleeve25 and the body. The coating also extends through the ports and aroundthe outer face of the flanges (not shown), and if desired, the outsidesurface of the body may likewise be coated with such a material. Typicalmaterials which may be used for the corrosion resistant plastic arechlorinated polyethers of molecular weight between 250,000 aud 350,000and epoxy resins, i.e., condensation products of epichlorohydrin andbisphenol A of molecular weight above 1,400, as well as epoxidizednovolak resins. The advantage of a structure of this type is the reducedcost of the body casting which may be 7 a ductile iron rather than thesomewhat more expensive corrosion resistant metal and metal alloys.

In the valve shown in FIG. 7, the interior configuration of the bore andthe configuration of the sleeve are essentially that of the bore andsleeve previously described. As shown, the plug 130 may also have acorrosion resistant plastic coating 135 on all fluid contacting surfacesthereof, in which event a material such as ductile iron may be used forthe plug.

It will be apparent to those skilled in the art that variousmodifications of the invention may be made without departing from thescope of the invention. For example, instead of the top cap sealassembly shown, that described in application Ser. No. 607,703, filedJan. 6, 1967, now Patent 3,406,707 and assigned to the same assignee,may be used. While relief areas 76a and 77a have been shown on theoutside surface of the sleeve, these relief areas may be placed on theinside surface of the sleeve in facing relation with the plug.

What is claimed is:

1. In a sleeve lined corrosion resistant plug valve adapted to controlflow of fluids, said valve including a body having a bore including abase, said bore extending transversely thereof and ports therethrough atleast two of which open into said bore in angularly spaced relation, atapered valve plug received in said bore and including port means foralignment with said body ports, said plug being of sufficiently smallerradial dimensions than said bore to establish an annular clearancebetween the opposed surfaces thereof, sleeve means received in saidclearance and having port means therein communicating with said bodyports, means maintaining said plug in sealing engagement with saidsleeve means during rotational movement from one position to another,said sleeve means being generally tubular and formed of fluorocarbonmaterial, each said body port opening into said bore in angularly spacedrelation including essentially straight side walls, the improvementcomprising relief means formed in said bore and having a radialdimension greater than the corresponding radial dimension of said bore,said relief means including axially spaced relief areas above and belowsaid angularly spaced ports and relieved portions extending towards andcommunicating with the top and bottom of each angularly spaced port,said relief means also including axially extending relief sections oneach side of said body and arcuately spaced with respect to each saidangularly spaced body port, the portion of said body between saidangularly spaced body ports and said relief sections forming flangesdefining the radial dimension of said bore, said relieved sections onthe same side of said body being separated from each other by portionsof said bore located between said angularly spaced body ports and beingpositioned between said axially spaced relief areas, said sleeve meansincluding relief pockets in the surface thereof and positioned oppositethe portion of said bore located between said angularly spaced bodyports, the remaining portion of said sleeve means being thicker incross-section than the crosssection of sad sleeve in the area of saidrelief pockets and being received in said relief means, the portions ofsaid sleeve received in said relief means being thicker than theremaining portions of said sleeve and being under greater sealingpressure than the remaining portions of said sleeve,

, 8 I and said bore and plug being essentially frusto-conical in shape.

2. In a sleeve lined plug valve as set forth in claim 1 wherein allinterior surfaces of said valve body in contact with fluid are coatedwith a relatively thin coating of corrosion resistant material, and saidcoating in the bore of the body being interposed between said body andsaid sleeve.

3. In a sleeve lined plug valve as set forth in claim 2 wherein allsurfaces of said plug exposed to contact with fluids are coated with arelatively thin coating of a corrosion resistant material.

4. In a sleeve lined plug valve as set forth in claim 1 wherein saidbase includes -a port therethrough opening into said bore, the port insaid-plug being registrable with one or the other of said angularlydisposed body ports and the port in said base.

5. In a sleeve lined plug valve as set forth in claim 1 wherein saidbody includes grooves means spaced axially relative to said relief areasand having a radial dimension greater than said relief areas, saidsleeve including portions thereof received in said groove means toprevent axial movement of said sleeve.

6. In a sleeve lined plug valve as set forth in claim 1 wherein theportion of said sleeve facing said bore in the area of said reliefpockets is in contact with said bore and under sealing pressure lessthan the portion of said sleeve received in said-relief means of saidbody.

7. In a sleeve lined plug valve as set forth in claim 1 wherein saidsleeve includes pressure relief means therein providing communicationbetween the back side of said sleeve and said plug port during rotationof said plug from one position to another position to prevent deflectionof said sleeve into said plug port during rotation thereof.

8. In a sleeve lined plug valve as set forth in claim 7 wherein thepressure relief means in said sleeve is located in the portion of saidsleeve received in the relief means in said body.

9. In a sleeve lined plug valve as set forth in claim 6 wherein saidsleeve is of polytetrafluoroethylene.

10. In a sleeve lined plug valve as set forth in claim 1 wherein saidflanges have an axial dimension essentially that of the port, andwherein the edge of said flanges adjacent the corresponding edge of saidsleeve ports engages said sleeve to prevent displacement thereof.

References Cited UNITED STATES PATENTS 1,915,161 6/1933 Jordan 137-62547XR 2,728,550 12/1955 Sinkler 251-317 2,911,187 11/1959 Owsley 251-316-3,061,269 10/ 1962 Sinkler 251-317 3,066,909 12/ 1962 Reed 251-3093,133,722 5/1964 McGuire et al. 251-309 3,199,835 8/1965 Freed 251-3093,276,739 10/1966 Freed 137-375 XR 3,310,278 3/1967 Smith 251-3173,438,388 4/1969 Schenck 137-375 HENRY T. KLINKSIEK, Primary ExaminerUS. Cl. X.R.

